At many snowfields and ski resorts, the weather is notoriously fickle, and there is often no snow or insufficient snow for enjoyable skiing. It is therefore necessary to augment natural snowfall with artificial snow.
It is known to make artificial snow by releasing a mist of atomised water and compressed air into a sub-zero temperature environment. The atomised water freezes to form minute ice crystals which, when accumulated, resemble snow. There are various known machines which have been developed to produce snow in this manner, and examples of such machines can be found in U.S. Pat. Nos. 2,676,471; 3,567,115; 3,716,190; 4,083,492; 4,004,732; 4,105,181 and 4,475,688.
However, the method cf making artificial snow in the abovedescribed manner has several inherent disadvantages. First, conventional snow making systems are very dependent on ambient conditions. The snow production rate, and the capacity of the snow making machines, decrease as the air temperature and humidity increase. Above zero degrees Celsius (0.degree. C.) snow cannot be produced efficiently using such known machines, unless an extremely low humidity exists. With the gradual heating of the earth due to the "greenhouse effect", the compressed air and atomised water method of making snow is becoming less effective.
Most revenue in commercial ski fields is generated on weekends and holidays. Such revenue can be maximised by ensuring that there is adequate (artificial) snow coverage during those peak use periods in the event of inadequate natural snow. Due to the fickleness of the weather however, there is no guarantee that the conventional systems will be able to operate to generate adequate snow coverage for these peak periods. Conversely, there are times, such as during the working week, when the revenue obtained from a relatively low number of skiers does not justify the high cost of creating the artificial snow by conventional methods and machines.
Secondly, known snow making machines are expensive to construct and operate. Since such snow making machines may remain idle when temperatures are above 0.degree. C. despite strong skier demand for snow, the snow machines do not fulfil their intended purpose and represent an inefficient use of large capital resources. Even if the temperature falls below zero, this normally occurs only during the night, and the machines are operative only about five hours in each day.
Thirdly, conventional snow making systems using compressed air and atomised water are not suitable for use in excessively windy weather or during rain periods, or near skiers.
Finally, the use of compressed air by the known snow making machines creates a loud noise level while those machines are operating, typically in the middle of the night. Such a noisy environment is detrimental to the wellbeing and sleep of skiers who may be staying at the ski lodges in the vicinity of the ski runs, and in any case, is generally inconsistent with the peaceful alpine environment of a typical ski field.
Despite the above limitations and disadvantages of known snow making systems, they have become increasingly popular and are virtually essential for a profitable ski field operation. Any prolonged period without snow can be financially disastrous for a commercial ski resort. For this reason, ski operators are forced to spend large amounts in capital expenditure and operating costs in providing the artificial snow making capacity.
It is an object of the present invention to provide an improved snow making method and apparatus which overcomes or substantially ameliorates, at least some of the disadvantages mentioned above.